KRV tower (upgrade) strategies

Long-time player but first time posting here. I wanted to see what people do with their towers in terms of upgrading.

Do you fill all the available tower spots before upgrading?

Do you upgrade all your towers to the same level before upgrading to the next tier?

Do you have specific final level upgrades that you always goto first/some you never use?

I personally tend to say yes to the first two questions and I'm still deciding on my last one. I'm not an impossible level player but I've played all the KR games and have a good sense for the basic strategy.

1) I usually upgrade a few key position towers up to tier 4 with maybe a couple abilities before going for more towers. I think that Vengeance lends toward this strategy even more than past games.

2) I don’t really think about that most of the time, but if the level layout is symmetrical, then I usually do do this.

3) Yes. Brutal Strike needs to be upgraded fully to be effective, as well as Gargoyles from Mausoleum, and usually even Harrassers’ Arrow Storm upgrade. I never buy higher levels on instakills in any of the games unless I have a lot of excess gold; shaving off a few seconds is not worth the usually extravagant pricing.

"Grammar is the logic of speech, even as logic is the grammar of reason." ~ Richard Chenevix Trench

"You don't have good grammar when you type with your fists." ~ C. F. Payne

1) No, I don't. Having a few strong towers is better than having un-upgraded towers all over the map spots. Upgrading a tower is significantly stronger than having two unupgraded ones.2) Depends on the level, since some levels require more firepower on one side.3) Melting Furnace's Red Hot Coals and Burning Fuel are a must. Bone Flingers' three upgrades are all good. Blazing Gem's Fourth Charge. Mausoleum's Gargoyles, and if any huge enemies, Possession. Dark Knights' Brutal Strike and Armor of Thorns. Depending on whether they're frontline blockers or backline attackers, Harassers get either Backstab or Arrow Storm.

I've used to upgrade towers to lvl 4 and go instantly for vital abilities, but now, as I've increased my understanding of the game, I actually plan ahead and often go for a few mid-tier towers instead of upgrading one (like I used to go for instant Rangers with Roots or Tesla with Overcharge in KR).However, sometimes tier 1 are really bad, and KRO is the best example of that (druids do laughable damage at 1, barracks can't shoot, archers have lower DPS and only 1 targets, low damage mages), and some of the towers (like Melting Furnace in KRV, basically, t1 at KRV sucks too) should be instantly upgraded to level 2 at least. Actually, spamming t2 is often quite good.There are rare exceptions: for example, in KR mage tower slow for 0,5 down with each shot, in KRF mages deal bonus damage for each tower build, in KRO they teleport back and that can be used at t1 already, so sometimes moderately spamming t1 is a strategy too (assuming you'll planned ahead their positions and how and when you'll upgrade them later).

As for KRV - I do the same. I plan ahead and instantly go for 2-4 lvl 2-3 towers. And THEN I transition to lvl 4 and skills of the most important tower.